Low spin arming fuze for autorotating munitions

ABSTRACT

An improved low spin arming fuze providing a safer and more reliable fuze for autorotating munitions is disclosed. The spin fuze provides for the arming of the fuze during initial spin-up due to the centrifugal force provided by the rotational velocity when the munition is deployed and permits initiation of the fuze upon spin decay, as occurring at impact. The fuze may ignite either the detonator or multiple pop-up charges combined with a delayed detonation of the munition.

Schultz, Jr.

n States tent H 1 [451 May 1, 1973 LOW SPIN ARMING FUZE FOR AUTOROTATING MUNITIONS [75] Inventor: Edward G. Schultz, Jr., Richmond,

Ind.

[73 Assignee: Arco Corporation, Richmond, Ind. [22] Filed: Aug. 18, 1971 [2]] App]. No.: 172,695 I [52] U.S. Cl. ..102/79, l02/7.2, 102/76 P [51] Int. Cl. ..F42c 15/22 [58] Field of Search 102/76, 79, 8O

[56] References Cited UNITED STATES PATENTS McLaslin et al ..l()2/79 Webb l02/79 Dixon 102/79 Gratton et al. 102/79 Primary ExaminerSamuel W. Engle Att0rneyCharles M. Hogan et al.

[ 7 ABSTRACT An improved low spin arming fuze providing a safer and more reliable fuze for autorotating munitions is disclosed. The spin fuze provides for the arming of the fuze during initial spin-up due to the centrifugal force provided by the rotational velocity when the munition is deployed and permits initiation of the fuze upon spin decay, as occurring at impact. The fuze may ignite either the detonator or multiple pop-up charges combined with a delayed detonation of the munition.

11 Claims, 9 Drawing Figures Patented May 1, 1973 3,730,101

' 2 Sheets-Sheet l INVENTOR.

K EDWARD s. SCHULTZ JR.

ATTORNEYS.

Patented May 1, 19 73 2 Sheets-Sheet 2 INVENTOR. EDWARD G. SCHULTZ JR.

7 71 7* F Z5 ATTORNEYS.

LOW SPIN ARMING FUZE FOR AUTOROTATIN MUNITIONS BACKGROUND OF THE INVENTION This invention relates generally to fuzes and more particularly to a spin fuze for use in autorotating munitions which are armed utilizing centrifugal forces.

Numerous centrifugal-inertia type fuzes are in existence. Many such fuzes have complex mechanism and many moving parts. It is, of course, well established that there is a greater chance for non-arming due to malfunction as the number of parts and in particular moving parts increases.

Accordingly, it is an object of this invention to provide a fuze having few moving parts and which is fail safe in operation.

Another object of this invention is to provide a fuze operational in response to the centrifugal force provided by rotational velocity when the munition is deployed.

Yet another object of this invention is to provide fuzes with great commonality of parts which will provide either ground burst or air burst using one basic fuze mechanism.

SUMMARY OF THE INVENTION This invention provides an improved spin fuze for autorotating munitions. The spin fuze is of simple and economical construction, operates in response to centrifugal forces and is fail safe in operation. The spin fuze comprises a firing pin assembly pivotallymounted on a slider which is locked in the safing position. The firing pin assembly cooperatively engages in a locking manner with a detonator carrying rotor to serve as an additional safing lock to prevent inadvertent arming. The slider is unlocked in response to centrifugal forces due to rotational velocity of the munition to permit the slider and firing pin assembly to move to the armed position.

In different embodiments of-this invention impact will ignite either the detonator or multiple pop-up charges followed by a delayed detonation. The resulting ground burst and air burst fuzes have considerable commonality of parts.

Other objects, details, uses and advantages of this invention will become apparent as the following description of exemplary embodiments thereof presented in the accompanying drawings proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS the parts of the low spin arming fuze of this invention;

FIG. 2 is a cross-sectional view of the fuze along the line 2-2 of FIG. 4;

FIG. 3 is a sectional view taken along the line 33 of FIG. 2, just below the base plate of the rotor housing, and showing the fuze in the safed position;

FIG. 4 is a sectional view taken along the line 4-4 of FIG. 2 showing the fuze in the safed position;

FIG. 5 is a view similar to FIG. 3 showing the fuze in the armed position;

FIG. 6 is a view similar to FIG. 4 showing the fuze in the armed-detonating position;

FIG. 7 is a fragmentary elevational sectional view showing the firing pin in the safed position;

FIG. 8 is a view similar to FIG. 7 showing the firing pin in the armed position; and

FIG. 9 is a sectional view, similar to FIG. 4, of another exemplary embodiment.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT Reference is now made to FIG. 1 of the drawings, which illustrates one exemplary embodiment of the improved spin fuze of this invention, which is designated generally by the reference numeral 10. The spin fuze 10 comprises an outer fuze housing or cup 12 of cylindrical shape in which a slider housing 14 is mounted. The slider housing 14 is formed with a channel 16 in which a slider 18 is placed for sliding movement therealong. The slider 18 is substantially U-shaped, as best seen in FIG. I, and includes a pair of upright supports 20 and 22.

A pair of slider locks 24 and 26 (FIGS. 1 and 3) are mounted in channels 28 and 30 of the slider housing 14. The channels 28 and 30 communicate with channel 16. Springs 32 and 34 bias the slider locks 24 and 26, respectively, inwardly to engage the leg portions of the slider 18 when the slider is in the safed position. The slider locks 24 and 26 cooperate with shoulders 36 and 38, respectively, of the slider 18 to lock in the safed position. Lock pins 40 and 42 are carried by the slider 18 to lock the sliders in the armed position, as will be explained hereinbelow.

Firing pin assembly, generally indicated as 44, is pivotally mounted to the vertical uprights 20 and 22 by a suitable means such as a pin 45. The firing pin assembly 44 comprises a camming body 46 of generally triangular shape and a firing pin 48 affixed to one surface thereof. Locking ear or finger S0 protrudes from one edge of the camming body 46.- A rotor housing 52 fits within the fuze housing 12 (FIG. 1) and rests on the top of slider housing 14. The base plate 53 of rotor housing 52 is formed with a substantially rectangular slot or channel 54 less than the width of the channel 16 in the slider housing 14. Thus, when assembled, the slider 18 is sandwiched in channel 16 by the base plate 53 of the housing 52. The slider 18 is free for linear sliding movement within the channel 16 (when slider locks 24 and 26 are not engaged) and is prevented from vertical movement or tilting by the overlap of the base plate 53 which extends slightly over the channel 16.

Vertical uprights 56 and 58 extend upwardly from the base plate 53 and support a cover plate 60 which may be secured thereto by any suitable mans such as by crimping the ends of the fuze housing 12. A rotor 62 is pivotally mounted between the base plate 53 and cover plate 60 by any suitable means such as rotor pin 64. One end of the rotor pin 64 is secured to the cover plate 60 by hole 83 and the other end extends through an aperture 55 in the base plate 53 (FIG. 1) and is secured in the slider housing 14 by a hole 25. In this manner, the rotor housing 52 is secured against rotation relative to the slider housing 14. A suitable biasing means, such as a torsion spring 66 is mounted on the rotor pin 64 to engage the rotor 62 in a known manner so as to bias the rotor in a counterclockwise direction (FIG. 4) inthe manner to be described hereinbelow.

Any suitable detonator 68 may be mounted in the bore 69 formed in rotor 62 to provide initiation of the explosive train for the fuze 10. A notch 70, complementary with ear 50, is formed in the rotor 62 to cooperatively receive the ear 50 (FIG. 4) when the firing pin assembly 44 is in the horizontal or safed position. When so engaged, the firing pin assembly 44 is prevented from pivoting movement upward and, in addition, the slider 18 is locked against movement towards the housing 12 due to the engagement of the ear 50 with the notch 70.

Referring now to FIGS. 2, 3 and 4, the fuze is shown in the safed position. In this condition, the slider 18 is locked at the inward end of channel 16 by the slider locks 24 and 26. The firing pin assembly 44 is pivotally mounted to the uprights 20 and 22 and is in a plane parallel to the base plate 53 such that the firing pin 48 is perpendicular to the base plate 53 and pointed towards the base plate (FIG. 2). The ear 50 is received in the notch 70 and spring 66 biases the rotor 62 against firing pin assembly 44. It can be seen in this position that the detonator 68 firing pin 48 are out-ofline and there is no accidental way in which the firing pin 48 may engage the detonator 68.

When a munition having the spin fuze 10 therein is deployed into the airstream, the munition will being autorotating due to its configuration. The fuze 10 begins arming at approximately 1,000 rpm when the slider locks 24 and 26 overcome the biasing force of springs 32 and 34 due to the centrifugal force provided by the rotational velocity of the munition. At this point, the locks 24 and 26 move toward the housing 12 to unlock the slider 18. At the same time, rotor 62 is moved in a clockwise direction (FIG. 4) against the biasing force of spring 66 due to centrifugal force. The rotor pivots about pin 64 to the housing 12 as shown in phantom line in FIG. 4. In this position, ear 50 is disengaged from notch 70 and the slider 18 is free to move towards the housing 12 due to the centrifugal force of the autorotating munition.

As best seen in FIGS. 1,3 and 5, the uprights 20 and 22 of slider 18 define a vertical slot 72 complementally formed to receive camming post 74 of slider housing 14. The top surface of post 74 is slightly higher than the bottom plane of the camming body 46. Thus, as the slider 18 moves towards the housing 12, the camming post 74 engages the edge 77 (FIGS. 7 and 8) of camming body 46. Further outward movement of the slider 18 causes the camming body 46 to be pivoted to the armed position shown in FIG. 8 by the camming post 74. It may also be noted that centrifugal force will assist in pivoting the body 46 to the armed position. The camming post 74, together with centrifugal force acting on the body 46, prevents the fuze assembly 44 from again returning to the safed position. The lock pins 40 and 42 secure the slider 18 in the armed position by moving outward into pin receiving grooves 76 and 78. respectively, due to the centrifugal forces acting on the pins.

Upon rotational velocity decrease or spin decay of a predetermined amount, the spring force of spring 66 will overcome the centrifugal forces acting on rotor 62. The spring 66 will cause rotor 62 to rotate counterclockwise as viewed in FIGS. 4 and 6. At the termination of the counterclockwise rotation of rotor 62, the

detonator 68 engages the firing pin 48 (FIG. 6) such that the detonator is ignited. The rotor 62 is provided with an aperture 80 at the top which is in communication with the detonator 68. Aperture 80 permits communication between the detonator 68 and a suitable means, such as a lead cup 82 mounted in the cover plate which in turn ignites the high explosive. It can be seen that when the rotor 62 is in the safed position, aperture is not aligned with the lead cup 82. At the point of detonation, the aperture 80 has moved into the in-line position with the lead cup 82. The aforedescribed fuze is typically described as a ground burst fuze. In other words, the high explosive is detonated upon impact.

In some instances, it is desirable that the munition detonate at a predetermined height above the ground level. Such munitions may be typically described as a pop-up munition. In these munitions, a delay train is initiated upon impact so that explosive charges may be ignited to cause the munition to jump up to a predetermined height wherein the main high explosive charge is detonated. An exemplary embodiment of a fuze for this type munition is illustrated in FIG. 9 of the drawings. The fuze illustrated in FIG. 9 is very similar to the fuze 10; therefore, such fuze will be designated generally by the reference numeral 10A and parts of the fuze 10A which are very similar to corresponding parts of the fuze 10 will be designated by the same reference numeral as fuze 10 also followed by the letter designation A and not described again. The main difference between the fuze 10A and the fuze 10 is in the rotor and detonator. In this embodiment, the rotor 62A is modified to accept a delay primer 88 and a delay detonator 90. Passage 92 provides communication between the delay primer and delay detonator. An aperture 84 is provided in the base plate 53 (FIG. 1). The aperture 84 provides communication with aperture 86 in the slider housing 14 (FIG. 1) so as to provide two communication paths for the explosive train. The arming fuze 10A is identical to that previously mentioned. Upon impact, the firing pin 48A ignites the delay primer. The primer provides a present time delay after which two explosive charges (not shown), one on each side of the munition, are ignited to cause the munition to jump up in the air. Communication with the explosive charges is achieved through the two communication paths aforedescribed, i.e., apertures 80, 82, 84 and 86. The delay detonator 90 is also simultaneously initiated and provides a delay until a predetermined height is reached after which the main high explosive charge is detonated through aperture and lead cup 87.

From the foregoing, it can be seen that the basic low spin arming fuze of this invention may be used for either ground burst or air burst applications. The fuze has a great commonality of parts. To convert from one type fuze to the other, it is only necessary to replace the rotor and rotor housing. In the airburst fuze, it is necessary that the rotor housing have an aperture through the base to establish communication between the delay primer and one external explosive charge. Thus, there are two communications paths from the rotor to the explosive charges.

It can be seen that this invention provides a low spin arming fuze for use in autorotating munitions which is initially locked in the safed position. Spin up of the mua planar camming body, said body supported in the nition due to deployment or the like will unlock a firing horizontal plane in the safed position and in the pin carrying slider so that the slider can move to the vertical plane in the armed position;

armed position. Movement of the slider cams the firing a firing pin affixed to the lower planar surface of pin assembly to the armed position so that upon spin 5 said camming body; and

decay the detonator carrying rotor can engage the fira camming post at the end of said slider housing ing pin to initiate the explosive train. Thus, this invenchannel, said camming post extending vertically tion provides a low spin arming fuze which is of simple upward to engage said cammingv body when said and economical construction, has few moving parts, is slider is moved from the safed position towards the fail safe in operation and is armed in response to the 10 armed position wherein said camming post encentrifugal force provided by rotational velocity when gages said camming body to cause said body to the munition is deployed. Accordingly, the objectives p lly r ta to h rm pos n. hereinbefore set forth have been accomplished. 4. The fuze as set forth in claim 3 further comprising While present exemplary embodiments of this invena locking ear formed along one edge of said camming tion have been illustrated and described, it will be body, said rotor including a notch complementally recognized that this invention may be otherwise variformed to receive said locking ear when said slider and ously embodied and practiced by those skilled in the rotor are in the safed position, said engagement of the art. locking ear and notch preventing pivotal movement of What is claimed is: said camming body about said vertical uprights and l. A spin armed fuze for use in autorotating munilinear movement of said slider relative to said rotor,

tions comprising: said ear being disengaged from said notch when said a slider housing, said housing being formed with a rotor is pivoted in response to centrifugal forces.

slider channel therein; 5. A fuze as set forth in claim 4 further comprising a a slider mounted in said slider housing channel or rotor housing mounted between said slider housing and movement therein; said rotor, said rotor housing having a rectangular slot first locking means engaging said slider for locking formed therein, said slot having a width less than the said slider in the safed position, aid locking means width of said slider housing channel wherein said slider being responsive to centrifugal force to unlock is held in said slider housing channel by said rotor houssaid slider; 3O ing.

a firing pin assembly pivotally mounted on said 6. The fuze as set forth in claim 5 further comprising slider, said assembly being in the horizontal plane second lock means cooperating between said slider and relative to said slider housing in the safed position said slider housing for locking said slider in the armed and in the vertical plane in the armed position; position.

a detonator-carrying rotor pivotally mounted to said 7. A spin armed fuze for use in autorotating munislider housing, said rotor cooperatively engaging tions comprising:

said firing pin assembly in the safed position, said a cylindrical slider housing, said housing being rotor pivoting away from said firing pin assembly formed with a slider channel transverse the rotain response to centrifugal forces due to rotational tional axis; velocity of the fuze; a slider mounted in said channel for linear movement means for camming said firing pin assembly from the therein, said slider being at the inward position safed position to the armed position when said when said fuze is in the safed condition and at the slider has been unlocked by said locking means outer position in the armed condition; and said slider has moved in said slider housing means for locking said slider in the safed position, channel to the armed position; and said means being responsive to centrifugal force to means for rotating said detonator-carrying rotor to unlock said slider;

engage said armed firing pin assembly when said a firing pin assembly including a planar camming means overcomes the centrifugal forces acting on body and a firing pin attached to one planar sursaid rotor wherein contact of a detonator in the fa ofsaid camming body; rotor with said firing pin assembly initiates the exmeans pivotally unting aid camming body in plosive train. spaced relation to said slider, said planar body hav- 2. A fuze as set forth in claim 1 in which said firing ing a firing pin attached thereto facing said slider pin assembly includes a locking ear and in which said in the safed condition and being pivotally rotated rotor includes a notch complementally formed to to the Vertical in the armed Position; receive said locking ear when said firing pin assembly a rotor pivotally mounted to said slider housing; said and said slider are in the safed position wherein pivotal r tor a ing a first position for cooperatively enmovement of said firing pin assembly is prevented and gaging the edge of said camming body when said said slider is prevented from sliding in said channel, slider and camming body are in the safed positi n, said ear being disengaged from said notch when said Said rotor having a Second position wherein said rotor is pivoted in response to centrifugal forces. rotor is pivotally rotated away from said camming 3. The fuze as set forth in claim 1 in which said slider body in response to centrifugal forces, said rotor includes a pair of vertical uprights at one end thereof, having a third position for engaging said firing pin said uprights defining a slot therebetween; when said slider has moved to the armed position; i said firing pin assembly being pivotally mounted at detonator means carried by said rotor wherein said the upper end of said vertical uprights, said firing detonator means is ignited when said rotor is urged -pin assembly comprising into the third position;

. means for camming said camming body from the safed condition to the armed condition during linear transverse movement of said slider in said slider housing channel; and

means for rotating said rotor to make contact with said firing pin when said means overcomes the centrifugal forces acting on said rotor in the second rotor position.

8. A fuze as set forth in claim 7 in which said camming body mounting means includes a pair of uprights protruding from the outward end of said slider, said uprights defining a slot therebetween; and

in which said camming means includes an upright post protruding from the outward end of said slider and said rotor, said rotor housing having a rectangular slot formed therein, said slot having a width less than the width of said slider housing channel and said rotor housing mounted so that said rotor housing slot overlies said slider housing channel to hold said slider therein.

10. The fuze as set forth in claim 9 comprising a locking ear formed along one edge of said camming body, said rotor including a notch complementally formed to receive said locking ear when said rotor is in the first position, said engagement of the locking ear with the notch preventing pivotal movement of said camming body about said vertical uprights and linear movement of said slider relative to said rotor, said locking ear being disengaged from said notch when said rotor is pivoted to the second position in response to centrifugal forces.

11. The fuze as set forth in claim 1 in which said rotor provides a preset time delay after which multiple explosive charges cause the munition to pop-up into the air followed by a second delay after which the explosive charge is detonated. 

1. A spin armed fuze for use in autorotating munitions comprising: a slider housing, said housing being formed with a slider channel therein; a slider mounted in said slider housing channel or movement therein; first locking means engaging said slider for locking said slider in the safed position, aid locking means being responsive to centrifugal force to unlock said slider; a firing pin assembly pivotally mounted on said slider, said assembly being in the horizontal plane relative to said slider housing in the safed position and in the vertical plane in the armed position; a detonator-carrying rotor pivotally mounted to said slider housing, said rotor cooperatively engaging said firing pin assembly in the safed position, said rotor pivoting away from said firing pin assembly in response to centrifugal forces due to rotational velocity of the fuze; means for camming said firing pin assembly from the safed position to the armed position when said slider has been unlocked by said locking means and said slider has moved in said slider housing chaNnel to the armed position; and means for rotating said detonator-carrying rotor to engage said armed firing pin assembly when said means overcomes the centrifugal forces acting on said rotor wherein contact of a detonator in the rotor with said firing pin assembly initiates the explosive train.
 2. A fuze as set forth in claim 1 in which said firing pin assembly includes a locking ear and in which said rotor includes a notch complementally formed to receive said locking ear when said firing pin assembly and said slider are in the safed position wherein pivotal movement of said firing pin assembly is prevented and said slider is prevented from sliding in said channel, said ear being disengaged from said notch when said rotor is pivoted in response to centrifugal forces.
 3. The fuze as set forth in claim 1 in which said slider includes a pair of vertical uprights at one end thereof, said uprights defining a slot therebetween; said firing pin assembly being pivotally mounted at the upper end of said vertical uprights, said firing pin assembly comprising a planar camming body, said body supported in the horizontal plane in the safed position and in the vertical plane in the armed position; a firing pin affixed to the lower planar surface of said camming body; and a camming post at the end of said slider housing channel, said camming post extending vertically upward to engage said camming body when said slider is moved from the safed position towards the armed position wherein said camming post engages said camming body to cause said body to pivotally rotate to the armed position.
 4. The fuze as set forth in claim 3 further comprising a locking ear formed along one edge of said camming body, said rotor including a notch complementally formed to receive said locking ear when said slider and rotor are in the safed position, said engagement of the locking ear and notch preventing pivotal movement of said camming body about said vertical uprights and linear movement of said slider relative to said rotor, said ear being disengaged from said notch when said rotor is pivoted in response to centrifugal forces.
 5. A fuze as set forth in claim 4 further comprising a rotor housing mounted between said slider housing and said rotor, said rotor housing having a rectangular slot formed therein, said slot having a width less than the width of said slider housing channel wherein said slider is held in said slider housing channel by said rotor housing.
 6. The fuze as set forth in claim 5 further comprising second lock means cooperating between said slider and said slider housing for locking said slider in the armed position.
 7. A spin armed fuze for use in autorotating munitions comprising: a cylindrical slider housing, said housing being formed with a slider channel transverse the rotational axis; a slider mounted in said channel for linear movement therein, said slider being at the inward position when said fuze is in the safed condition and at the outer position in the armed condition; means for locking said slider in the safed position, said means being responsive to centrifugal force to unlock said slider; a firing pin assembly including a planar camming body and a firing pin attached to one planar surface of said camming body; means pivotally mounting said camming body in spaced relation to said slider, said planar body having a firing pin attached thereto facing said slider in the safed condition and being pivotally rotated 90* to the vertical in the armed position; a rotor pivotally mounted to said slider housing; said rotor having a first position for cooperatively engaging the edge of said camming body when said slider and camming body are in the safed position, said rotor having a second position wherein said rotor is pivotally rotated away from said camming body in response to centrifugal forces, said rotor having a third position for engaging said firing pin when said slider has moved to the armed posItion; detonator means carried by said rotor wherein said detonator means is ignited when said rotor is urged into the third position; means for camming said camming body from the safed condition to the armed condition during linear transverse movement of said slider in said slider housing channel; and means for rotating said rotor to make contact with said firing pin when said means overcomes the centrifugal forces acting on said rotor in the second rotor position.
 8. A fuze as set forth in claim 7 in which said camming body mounting means includes a pair of uprights protruding from the outward end of said slider, said uprights defining a slot therebetween; and in which said camming means includes an upright post protruding from the outward end of said slider housing channel, said upright post and slider uprights being complementally formed for engagement therebetween in the armed condition, said upright post engaging said camming body to cause pivotal rotation of said camming body as said slider moves linearly from the safed to the armed condition.
 9. The fuze as set forth in claim 8 further comprising a rotor housing mounted between said slider housing and said rotor, said rotor housing having a rectangular slot formed therein, said slot having a width less than the width of said slider housing channel and said rotor housing mounted so that said rotor housing slot overlies said slider housing channel to hold said slider therein.
 10. The fuze as set forth in claim 9 comprising a locking ear formed along one edge of said camming body, said rotor including a notch complementally formed to receive said locking ear when said rotor is in the first position, said engagement of the locking ear with the notch preventing pivotal movement of said camming body about said vertical uprights and linear movement of said slider relative to said rotor, said locking ear being disengaged from said notch when said rotor is pivoted to the second position in response to centrifugal forces.
 11. The fuze as set forth in claim 1 in which said rotor provides a preset time delay after which multiple explosive charges cause the munition to pop-up into the air followed by a second delay after which the explosive charge is detonated. 